Dental composites must undergo sufficient polymerization to develop the physical and mechanical properties that provide durability of the restoration. The goal of this research is to optimize cure efficiency. There are four specific aims: 1) determine the type and concentration of photosensitizer and of the amine accelerator that result in optimal polymerization, 2) determine if polymerization can be improved by using two photosensitizers, 3) determine the most appropriate light source, 4) apply the developed visible light initiating system in polymerization of dimethacrylate anhydrides monomers. Experimental composites, similar in resin formulation and filler content but with systematically varied photosensitizer concentration (0.1 approximately 1.6 wt% of resin) will be prepared. Camphoroquinone will be used to determine an efficient amine accelerator. Optimal cure as a function of DC and Knoop hardness (KHN) of three currently used and one novel photosensitizer, and a mixture of two photosensitizers will be measured. Analysis of maximum DC and KHN values for the various photosensitizers will be done to determine the most efficient one. A light emitting diode (LED) whose emission adequately overlaps the absorption spectrum of photosensitizer will be chosen.